Sample well strip

ABSTRACT

A multiple cuvette strip comprises a plurality of wells and a reversible interlocking device. The well strips can be reversibly interlocked to other well strips to form a sample holder system. One embodiment of a well strip comprises a flange and a slot to form a reversible interlocking device.

TECHNICAL FIELD

[0001] The present invention relates generally to sample wells forholding samples to be analyzed in an automated sample analyzer, and,more particularly to sample wells for holding body fluid samples foranalysis in an automated medical sample analyzer for medical diagnostictest procedures.

BACKGROUND

[0002] A sample well strip has a plurality of sample wells which are notin fluid communication with each other, but which are physicallyconnected to each other and typically arranged in a linear array. Thesample well strip is typically used for holding samples, such asaliquots of a reaction mixture, environmental samples, blood, urine orfractions of samples thereof, in instruments, such as automated sampleanalyzers, for use in medical diagnostic test procedures.

[0003] A goal of medical laboratories is to enhance laboratoryefficiency by analyzing as many samples as possible in a given timeperiod, while at the same time minimizing the number of interactionsbetween laboratory personnel, the samples, and sample analyzers. Samplewell strips have been developed that allow multiple samples to be loadedinto an automated sample analyzer all at once. Generally, however, eachsample well strip is individually loaded, well strip-by-well strip, andmanually introduced into the automated sample analyzer in a positionready to receive the test sample. Thus, the number of sample well stripsthat can be loaded onto the sample analyzer, and the number of samplesthat can be analyzed per unit time, is limited by the number of wellstrips that can be arranged, typically side-by-side, on the loading trayof the automated sample analyzer.

[0004] Therefore, it would be desirable to provide a sample well stripcomprising a plurality of sample wells that increases the number ofsamples that are analyzed per unit time and that minimizes theinteractions between laboratory personnel and individual sample wellstrips. The goal of this invention is to enhance the efficiency of theautomated sample analyzer's performance and capacity by a sample wellstrip that increases the number of well strips that can be loaded ontothe analyzer at any one time.

SUMMARY OF THE INVENTION

[0005] In general, the advantages of the present invention providesample well strips that increase the number of samples that can beanalyzed by a sample analyzer within a unit of time and reduce thenumber of interactions between laboratory personnel and the individualwell strips.

[0006] In one aspect, the invention relates to a sample holder systemhaving a first and at least a second well strip having a plurality ofwells and an interlocking device disposed on the well strips. Theinterlocking device reversibly engages the first well strip with thesecond well strip. In one embodiment, the interlocking device has afirst engagement piece positioned on the first well strip and a secondengagement piece positioned on the second well strip. The first andsecond engagement pieces reversibly interlock to form a sample holdersystem.

[0007] In another embodiment, the first engagement piece is positionednear the first end of the first well strip and the second engagementpiece is positioned near the second end of the second well strip. Inanother embodiment, the first engagement piece is positioned on a firstside wall of the first well strip and the second engagement piece ispositioned on a second side wall of a second well strip. In thisembodiment, for example, the second engagement piece is positioned atthe second end of the first well strip and the first engagement piece ispositioned at the second end of the second well strip. In anotherembodiment of the invention, the first well strip and at least thesecond well strip are substantially similar.

[0008] In one embodiment of the invention, the first engagement pieceincludes a flange and the second engagement piece includes a slot.Alternatively, the second engagement piece includes a slot and a slit.In one embodiment, the first engagement piece positioned at the firstend of the first well strip has a flange and the second engagement piecepositioned at the first end of the second well strip has a slot, or,alternatively, a slot and a slit. The interlocking device according tothe invention includes a first engagement piece and a second engagementpiece.

[0009] In another aspect, the invention relates to a first well stripincluding a plurality of wells, a first engagement piece, and a secondengagement piece. The first engagement piece and second engagement piececooperate to reversibly attach a first well strip and a second wellstrip.

[0010] In another embodiment of this aspect of the invention, the firstwell strip includes a first engagement piece substantially positionednear a first end of the first well strip and a second engagement piecesubstantially positioned near a second end of the well strip. In yetanother embodiment of this aspect of the invention, the first engagementpiece is positioned on a first side wall and the second engagement pieceis positioned on a second side wall of the well strip. In a furtherembodiment, the first engagement piece is a flange and the secondengagement piece is a slot, or alternatively, the second engagementpiece is a slot and a slit.

[0011] In another aspect, the invention relates to a method forincreasing the load capacity of an automated sample analyzer. The methodaccording to the invention includes the steps of interlocking a firstwell strip with at least a second well strip to form a sample holdersystem and loading a plurality of sample holder systems onto theautomated sample analyzer. In one embodiment, the method furtherincludes the steps of detaching a first well strip from the sampleholder system by disengaging the first well strip from the second wellstrip, moving the first well strip, and analyzing the samples in thewells of the first well strip. The plurality of well strips areinterlocked by slidably moving the first well strip horizontallyrelative to at least a second well strip to engage the first and secondwell strips.

[0012] In one embodiment according to this aspect of the invention, thesample held by a well of a well strip is a body fluid, for example,blood, urine, plasma, or serum. The sample can be analyzed in the wellof a well strip for a coagulation disorder, electrolyte concentration orto determine the presence or concentration of a drug.

[0013] The foregoing and other objects, features and advantages of thepresent invention disclosed herein, as well as the invention itself,will be more fully understood from the following description ofpreferred embodiments and claims, when read together with theaccompanying drawings. In the drawings, like reference charactersgenerally refer to the same parts throughout the different views. Thedrawings are not necessarily to scale, emphasis instead generally beingplaced upon illustrating the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a side perspective view of a well strip with four samplewells.

[0015]FIG. 2 is a perspective view of a preferred embodiment of a wellstrip.

[0016]FIG. 3A is a top view of a first engagement piece flange.

[0017]FIG. 3B is a side view of a second engagement piece slot.

[0018]FIG. 3C is a top view of two reversibly engaged well strips.

[0019]FIG. 4 is a perspective view of a sample holder system comprisinga plurality of well strips.

[0020]FIG. 5 is a perspective view of a plurality of sample holdersystems in a vertical side-by-side arrangement.

[0021]FIG. 6 is a perspective view of a well strip with cylindricallyshaped wells.

[0022]FIG. 7 is a sectional view of a well strip with funnel-shapedwells.

[0023]FIG. 8 is a perspective view of a portion of a well strip and alight transmission path through a sample.

[0024]FIG. 9 is a perspective view of a portion of a well strip and alight transmission path through a sample.

[0025]FIG. 10 is a bottom view of a sample holder system.

DETAILED DESCRIPTION

[0026] Each of the embodiments of the invention described below have thefollowing common features: a well strip comprising a plurality of samplewells, each well dimensioned to hold a sample, and each well stripreversibly attachable to at least one other well strip to form a sampleholder system.

[0027] Referring to FIG. 1, in general, according to the invention, asample well strip 111 has a plurality of wells 108 a, 108 b, 108 c, 108d, generally 108 extending from a first end wall 101 of the well strip111 to a second end wall 103 of the well strip. For example, asillustrated in FIG. 1, in one embodiment, the sample well strip 111 hasfour wells 108. In a particularly preferred embodiment of the invention,shown in FIG. 2, the well strip 111 is approximately 50-100 mm inlength, preferably 66 mm in length, approximately 5-15 mm in width,preferably 9 mm in width, and approximately 12-24 mm in height,preferably 18 mm in height from the well base 112 to the top 113 of thewell. The sample well strip 111 is manufactured from materials which arechemically and optically suitable, for example but not limited to,polystyrene, acrylic, or TPX (polyolefin).

[0028] The sample wells 108 in a well strip 111 are typically used forholding one of a variety of test samples, such as aliquots of a reactionmixture, an environmental sample, blood, urine, joint fluid,cerebrospinal fluid, and other body fluids or fractions thereof for usein chemical assays, diagnostic test procedures, drug testing, and otherassays. For example, blood, serum, or plasma samples held in samplewells 108 are analyzed in sample wells 108 to determine, for example,the concentration of analytes such as glucose, lactate, electrolytes,enzymes, in the sample, or for analysis of coagulation disorders. Fluidsother than body fluids can also be analyzed in sample wells 108. Forexample, drinking water placed in sample wells 108 can be analyzed forpurity or contamination.

[0029] A test sample placed in sample well 108, according to theinvention, can be analyzed in various instruments, such as automatedsample analyzers for in vitro diagnostic analysis. Examples of suchautomated analyzers are manufactured by Instrumentation LaboratoryCompany, (Lexington, Mass.).

[0030] With continued reference to FIG. 1 and with reference to FIG. 2,each sample well 108 of the well strip 111 is adjacent to at least oneother well 108 to form an array of wells from a first end wall 101 to asecond end wall 103 along the longitudinal axis 109 of the well strip111. The number of sample wells 108 in a well strip 111 may vary. Forexample, a well strip 111 can have anywhere from 2 to 100 wells 108.

[0031] In another aspect of the invention, a sample well strip 111comprises one or more first engagement pieces, generally 200, such as aflange or a peg, located on a first side wall 121 of the sample wellstrip 111, shown in FIG. 2, and one or more second engagement pieces,generally 201, such as a slot, shown in shadow in FIG. 2, located on thesecond side wall 124 of the strip 111, the second side wall beingopposite to the first side wall. In a particular embodiment, first sidewall 121 and second side wall 124 of a sample well strip 111 areparallel to each other (also see FIG. 3C). When two such sample wellstrips 111 are placed with the first side wall 121 of a first well strip111 abutting the second wall 124 of a second well strip 111, the firstengagement piece 200 of the first well strip 111 reversibly engages thesecond engagement piece 201 of the second well strip 111. Thus, thefirst engagement piece 200 of a first well strip 111 reversiblyinterlocks with the second engagement piece 201 of a second well strip111. The combination of the first engagement piece 200 of one well strip111 with the second engagement piece 201 of a second well strip 111comprises a reversible interlocking device. As shown in FIG. 4, when oneor more well strips 111 are interlocked, the side walls 121 and 124 ofthe well strips 111 are parallel, the first end 101 of each well stripis aligned with the first end 101 of each other well strip 111, and thesecond end 103 of each well strip is aligned with the second end 103 ofeach other well strip 111.

[0032] In other embodiments (not shown) of this aspect of the invention,the reversible interlocking device may include a first engagement piece200 such as hook, and a second engagement piece 201, such as an eye.Other combinations of the first engagement piece 200 and secondengagement piece 201 include but are not limited to, respectively, ahook and a hook, peg and a hole, the two components of a dovetail joint,and various types of first and second adhesive surfaces, such aschemical or fabric adhesives. In a particular embodiment, the firstengagement piece and the second engagement piece interlock, i.e., thefirst engagement piece engages the second engagement piece andtemporarily locks in place without permanently deforming the first orthe second engagement piece. The first and second engagement pieces areseparable following interlocking of the first and second engagementpieces without permanently deforming either the first or secondengagement piece.

[0033] In a particular embodiment, the first engagement piece 200 andthe second engagement piece 201 are reversibly interlocked. A first wellstrip 111 a is interlocked with a second well strip 111 b by engagingthe first engagement piece 200 of the first well strip 111 a with thesecond engagement piece 201 of a second well strip 111 b. The secondwell strip 111 b may be interlocked with a third well strip 111 c byengaging the first engagement piece 200 of the second well strip 111 bwith the second engagement piece 201 of a third well strip 111 c, and soon. In other embodiments, the second engagement piece 201 of the firstwell strip 111 a interlocks with the first engagement piece 200 of thesecond well strip 111 b, and so on. The location of the first engagementpiece 200 and the second engagement piece 201 on either the first,second, third, or more well strips 111, is not important as long as atleast one first engagement piece 200 on a well strip 111, can interlockwith at least one second engagement piece 201 on an adjacent well strip111. Well strips 111 that are interlocked via the interlocking deviceengaging a first engagement piece 200 and a second engagement piece 201are detached from each other by disengaging the first and secondengagement pieces.

[0034] In a particular embodiment, the reversible interlocking deviceincludes a clip-like flange first engagement piece 200 and acomplementary slot second engagement piece 201. Flange 200, illustratedin FIG. 3A, comprises a cantilevered arm 143 that is attached at thefixed end of the arm 143 to the first side wall 121 or the second sidewall 124 (not shown) near one end of the well strip 111 (also see FIG.2). The opposite end 147 of cantilevered arm 143 is free, i.e.,unattached to a side wall of well strip 111. Flange 200 has a first bendat elbow 144 closest to the attachment point of flange arm 143 to theside wall of the well strip 111. The elbow 144 is distanced 1.0-2.0 mm,preferably 1.75 mm from the side wall of the well strip 111. The flangearm 143 is 4-6 mm, preferably 5.20 mm, at the widest dimension of theflange arm 143 indicated by arrow 149 in FIG. 3A. A second bend ispositioned at elbow 146, near the free end 147 of the flange arm 143.The outside portion of the bend of the second elbow 146 touches ornearly touches the side wall of well strip 111. Flange arm 143 flexes atits point of attachment to the side wall of well strip 111.

[0035] A second engagement piece, comprising a slot 201, illustrated inFIG. 3B, is dimensioned to substantially fit the first engagement piece200 of the reversible interlocking device and is positioned near orpreferably at one end of well strip 111 (see FIG. 2). In a particularlypreferred embodiment, slot 201 is 5-6 mm, preferably 5.25 mm in heightindicated by arrow 250 and 2.5-3.5 mm, preferably 3.0 mm wide, indicatedby arrow 260 in FIG. 3B.

[0036] In a particular embodiment of a reversible interlocking device,the first engagement piece comprises a flange and the second engagementpiece comprises a slot. The second engagement piece 201 may furtherinclude a slit 202. As illustrated in FIGS. 2 and 3b, slit 202 is avertically oriented, elongated hole through wall 121 or wall 124positioned 2-5 mm from slot 201. As shown in FIG. 3C, viewedschematically from the top of well strips 111 a and 111 b, with flange200 engaged in slot 201, the curved portion 146 of the free end 147 ofthe cantilevered flange 200 is seated “home” and registers in slit 202.When flange 200 is seated in slit 202, the tension in flange arm 143 isrelaxed and the interlocking device is reversibly locked.

[0037] In a particular embodiment of the invention, illustrated in FIG.2, a well strip 111 with four wells 108 a, 108 b, 108 c, 108 d includesa first engagement piece 200 on the first side wall 121 of well strip111 near one end wall 101 of the strip, and a second engagement piece201 located on the second side wall 124 of the well strip 111 at thesame end 101 of the well strip 111. Another first engagement piece 300shown in shadow in FIG. 2, is located on the second side wall 124 of thewell strip 111 at the opposite end wall 103 of the strip 111, and asecond engagement piece 301 is located on the first wall 121 of the wellstrip 111 at the end wall 103 of the strip 111 on the side wall 121opposite the first engagement piece 300.

[0038] A particular embodiment of the invention shown in FIGS. 1 and 2,is a well strip 111 with flange 200 on the wall opposite slot 201 andslit 202 of the well strip 111 at the first end 101, and flange 300 onthe wall opposite to the slot 301 and the slit 202 located at the secondend 103. Thus, a well strip 111 having this configuration is reversiblyengageable with any other well strip 111 having an identicalconfiguration, to form a sample holder system 150 illustrated in FIG. 4.

[0039] Other embodiments of the invention include sample well strips 111having a first engagement piece 200 on the first end 101 of first sidewall 121 of the sample well strip 111, and another first engagementpiece 300 on the second end 103 of the first side wall 121 of the samplewell strip 111. Alternatively, in another embodiment, first engagementpiece 200 and second engagement piece 201 are on the same or oppositeside walls of the sample well strip 111 and located anywhere along thelongitudinal axis 109 of the sample well strip 111 as long as at leastone first engagement piece 200 of a first sample well strip 111reversibly interlocks with at least one second engagement piece 201 of asecond sample well strip 111.

[0040] A sample holder system 150, illustrated in FIG. 4, is formed byinterlocking two or more sample well strips 111 together, for example,sample well strip 111 a and sample well strip 111 b. In one embodimentof the invention, interlocking is accomplished by sliding the flange 200on the first side wall 121 near the first end 101 of the first samplewell strip 111 a into the slot 201 on the second side wall 124 near thefirst end 101 of the second sample well strip 111 b, and sliding theflange 300 on the second side wall 124 near the second end 103 of thesecond sample well strip 111 b into the slot 301 on the first side wall121 near the second end 103 of the first sample well strip 111 a. Thetwo interlocked sample well strips 111 a and 111 b are separated bysliding the flanges of each well strip out of the slots of each wellstrip 111 to unlock the two sample well strips 111 a and 111 b.

[0041] Using the same interlocking technique, any number of well strips111 can be interlocked to each other to form a sample holder system 150as shown in FIG. 4. For example, a sample holder system 150 may includeanywhere from 2 to 100, preferably 10 well strips 111 a-111 j. The sizeof the sample holder system 150 is determined by the number of wellstrips 111 that are interlocked. An advantage of the reversibleinterlocking system described herein is that this configuration allowsany number of well strips 111 to be interlocked to form a sample holdersystem 150.

[0042] The sample holder system 150, shown in FIG. 4, may be stackedside-by-side with a plurality of sample holder systems 150. For example,each sample holder system 150 may be arranged in a vertical orientation,i.e., with end 101, end 103, first wall 121, or second wall 124 restingon conveyor belt 160, as shown in FIG. 5. A series of sample holdersystems 150 can be oriented in this manner and stacked side-by-side on aconveyor belt 160 of an automated sample analyzer instrument. In thisorientation, a greater number of well strips 111 can be loaded onto aconveyor belt 160 per unit area than sample holder systems 150 arrangedin a horizontal orientation, i.e., with the bottom 112 or top 113 ofwell strip 111 resting on conveyor belt 160. Each well strip 111 ofsample holder system 150 is separated one at a time from the adjacentwell strip 111 for sample analysis in the automated sample analyzer.

[0043] A sample well 108 can have a variety of shapes. For example, inone embodiment of a well 108, the inside dimension of sample well 108 isrectangular as shown in FIG. 1. In other embodiments, the insidedimension of well 108 is cylindrical as shown in FIG. 6, orfunnel-shaped as shown in FIG. 7.

[0044] In a preferred embodiment of the invention, well 108, as shown inFIG. 7, is substantially funnel-shaped with a substantiallyflat-bottomed base 112. The funnel-shape geometry of the well narrowsfrom the top portion of the well 108, where sample and reagents areadded to the well, to the bottom portion, thereby minimizing the samplevolume necessary to run an analysis of the sample. The volume of samplerequired is only that volume of sample that will fill the volume of thewell 108 where optical windows 116 are located. Therefore, typically,only a small amount of fluid sample, in the range of 25-500micro-liters, preferably 150 micro-liters, is needed for an assay.

[0045] Other well shapes are possible and the shape of the well is notlimited to the embodiments illustrated. The well can be any shape aslong as there is substantially no optical distortion of the wall of well108 where the optical window 116 is located.

[0046] A sample well 108, illustrated in FIG. 1, in one embodiment, hasan open top 113, a base 112, and four walls including a first side wall121 a and a second side wall 124 a. First wall 121 a and second wall 124a have a top portion substantially adjacent to the top 113 and a bottomportion substantially adjacent to the base 112. In one embodiment, thebottom portion of the first wall 121 a and second wall 124 a includes anoptical window 116.

[0047] For analysis by an optical reader in an automated analyticalinstrument, for example, illustrated in FIG. 8, the bottom portion ofthe first wall 121 a and second wall 124 a of the well 108 have opticalwindows 116 a and 116 b located on opposing bottom portions of the well108. Optical windows 116 a and 116 b allow transmission of light of oneor more wavelengths from a source 119 substantially along the directionof arrow (a) through the first optical window 116 a, through the sample,through the second optical window 116 b, and then to an optical detector117 positioned on the opposite side of the well 108, to obtain anoptical reading of the sample. An optical window may be needed tomaximize transmission of light of a specific wavelength from its source119 through the sample to the optical detector 117 if the walls of thesample well 108 are otherwise substantially non-transmissive of thatwavelength. Preferably the optical windows allow the light from thesource 119 to pass through the optical windows 116 a, 116 b with minimalor insubstantial distortion. The optical windows 116 a, 116 b preferablyhave optically clear and flat surfaces.

[0048] The location of the optical window 116 on the well 108 is notlimited to that depicted in FIG. 8. Referring to FIG. 9, for example, inone embodiment, the optical window 116 is located in the base 112 of thewells 108 and the source 119 of the transmitted light (a) is locatedabove the top 113 of the well 108. The transmitted light for sampleanalysis passes through the sample, through the optical window in thebase 112, to the detector 117 positioned as illustrated in FIG. 9 belowthe base 112. Alternatively, the transmitted light may pass in theopposite direction, with the source of transmitted light below the base112 of the well 108, the transmitted light passing through the opticalwindow in the base 112, through the sample, and finally through the top113 of the well 108 where the detector 117 is positioned (not shown). Inyet another embodiment, the source 119 of light may be located at thetop 113 or bottom 112 of well 108 and the detector 117 may be located atthe side of well 108. In these embodiments, multiple well stripsattached to each other can be subjected to analysis.

[0049] The funnel-shaped wells provide an additional important featureof one aspect of the invention. In one embodiment, illustrated from thebottom of a sample holder system 150 in FIG. 10, the base 112 of eachwell in a well strip 111 is spaced apart from the base 112 of theadjacent well in an adjacent well strip 111, while the well strips areoriented parallel to one another. Thus, the funnel-shaped wells preventoptical windows 116 located in the bottom portion of each well 108 fromrubbing against the bottom portion of the corresponding well 108 in theadjacent well strip 111 when the well strips 111 are arrangedside-by-side. When optical windows 116 are located in the bottom portionof the well 108, the funnel-shape prevents optical windows 116 ofadjacent well strips 111 aligned side-by-side, from scratching orotherwise damaging the optical window 116 of an adjacent well strip 111,thereby altering the optical characteristics of the windows.

[0050] While the various embodiments of the present invention have beenillustrated, it is within the scope of the present invention to have asample holder comprising a well strip with a different number of wells,various well shapes and interlocking devices to allow a multiple arraysof well strips to be loaded onto an instrument such as automated sampleanalyzer. Variations and modifications of what is described herein willoccur to those of ordinary skill in the art without departing from thespirit and the scope of the invention as claimed. Accordingly, theinvention is to be defined not by the preceding illustrative descriptionbut instead by the spirit and scope of the following claims

What is claimed is:
 1. A sample holder system for an automated sampleanalyzer, comprising: a first well strip comprising a plurality of wellsand a first end and a second end; at least a second well stripcomprising a plurality of wells and a first and a second end; and aninterlocking device comprising a first engagement piece disposed on saidfirst well strip and a second engagement piece disposed on the secondwell strip wherein said first and second engagement pieces cooperate toreversibly attach said first well strip with said second well strip toform a sample holder system.
 3. The sample holder system of claim 2wherein said first well strip and said second well strip aresubstantially the same.
 4. The sample holder system of claim 2 whereinsaid first engagement piece is positioned substantially adjacent thefirst end of the first well strip and the second engagement piece ispositioned substantially adjacent the second end of said second wellstrip.
 5. The sample holder system of claim 2 wherein said firstengagement piece is positioned on a first side wall of said first wellstrip and said second engagement piece is positioned on a second sidewall of said second well strip.
 6. The sample holder system of claim 2wherein said first and second engagement pieces are reversiblyinterlockable by horizontally sliding said first well strip relative tosaid second well strip.
 7. The sample holder system of claim 2comprising: a second engagement piece positioned at the second end ofthe first well strip; and a first engagement piece positioned at thesecond end of the second well strip.
 8. The sample holder system ofclaim 1 wherein said first engagement piece comprises a flange and saidsecond engagement piece comprises a slot and a slit.
 9. The sampleholder system of claim 5 wherein said first engagement piece positionedat the first end of the first well strip comprises a flange, and saidsecond engagement piece positioned at said second end of said secondwell strip comprises a slot and a slit.
 10. The sample holder system ofclaim 7 wherein said second engagement piece positioned at the secondend of said first well strip comprises a slot and said first engagementpiece positioned at said second end of said second well strip comprisesa flange.
 11. The sample holder system of claim 1 wherein saidinterlocking device comprises a first engagement piece and a secondengagement piece.
 12. A well strip, comprising: a plurality of wells; afirst engagement piece; and a second engagement piece, wherein saidfirst engagement piece is configured to interlock with a complementarysecond engagement piece of another well strip, and said secondengagement piece of said well strip is configured to interlock with acomplementary first engagement piece of another well strip.
 13. The wellstrip of claim 12 wherein said first engagement piece is substantiallypositioned near a first end of said well strip and said secondengagement piece is substantially positioned near a second end of saidwell strip.
 14. The well strip of claim 12 wherein said first engagementpiece is positioned on a first wall of said well strip and said secondengagement piece is positioned on a second wall of said well strip. 15.The well strip of claim 12 wherein said first engagement piece comprisesa flange and said second engagement piece comprises a slot and a slit.16. The first well strip of claim 13 further comprising a secondengagement piece at said first end and a first engagement piece at saidsecond end.
 17. A method for increasing the load capacity of anautomated sample analyzer, comprising the step of: interlocking at leasta first well strip and a second well strip together to form a sampleholder system, said first and second well strips comprising a pluralityof sample wells.
 18. The method of claim 17 further comprising: loadinga plurality of said sample holder systems onto said automated sampleanalyzer; detaching a first well strip from said sample holder system bydisengaging said first well strip from a second well strip; moving saidfirst well strip; and, analyzing said samples in said plurality of wellsin said first well strip.
 19. The method of claim 17 whereininterlocking a plurality of well strips to form a sample holder systemcomprises slidably moving said first well strip horizontally relative tosecond well strip to engage said first and second well strips.
 20. Themethod of claim 17 further comprising introducing a sample into saidsample wells wherein said sample comprises a body fluid.
 21. The methodof claim 20 wherein said body fluid comprises blood.
 22. The method ofclaim 20 wherein said body fluid comprises urine.
 23. The method ofclaim 20 wherein said body fluid comprises serum.
 24. The method ofclaim 18 wherein said sample analysis comprises analyzing said samplefor a coagulation disorder.
 25. The method of claim 18 wherein saidsample analysis comprises analyzing said sample for electrolyteconcentration.
 26. The method of clam 18 wherein said sample analysiscomprises analyzing said sample to determine the presence orconcentration of a drug.
 27. A sample holder system comprising: a firstwell strip comprising a plurality of wells, a first and second sidewall, and a first and second end; and, at least a second well stripcomprising a plurality of wells, a first and second side wall, and afirst and a second end; each of said first well strip and said at leasta second well strip further comprising a flange on said first end ofsaid first side wall, a slot on said second end of said first side wall,a slot on said first end of said second side wall, and a flange on saidsecond end of said second side wall, wherein said slot and flange ofsaid at least a second side wall of said first well strip interlockswith said flange and said slot of said first side wall of said secondwell strip to form a sample holder system.